"In Libya, a regime that has lost all legitimacy has declared war on its people," Mr. Ban said. "It is up to us, the community of nations, to stand against this crime."

Ban was speaking 48 hours after the UN Security Council had voted unanimously at a rare Saturday session to adopt a resolution targeting the regime of Col. Muammar Qaddafi. In addition to imposing economic sanctions on Mr. Qaddafi, his family, and the governing elite, the measure established an arms embargo on Libya and referred it to the International Criminal Court (ICC) in The Hague for possible investigation of crimes against humanity.

Within days, the 192-member UN General Assembly would go on to suspend Libya from the UN's Human Rights Council – a first for the Assembly, which is dominated by developing nations. Now the Security Council appears poised to introduce a resolution that would call for the international community to enforce a no-fly zone over Libya. In addition, the ICC's chief prosecutor has announced he has grounds to formally launch an investigation of the crimes committed by Qaddafi and his cohorts against the Libyan people.

The flurry of action by the normally plodding UN conjured up a past warning from former President George W. Bush – that the UN risked irrelevancy if it could not act on a pressing international crisis.

Now, the question is whether the UN is indeed suddenly relevant.

Even the UN's strongest proponents acknowledge that much remains unresolved in Libya, with the fighting there threatening to deteriorate into a bloody stalemate and additional measures for pressuring Qaddafi – including imposition of a no-fly zone – under international consideration. UN critics say the global institution is still stuck on lofty words when action is what is required.

Tuesday's expected introduction of a no-fly zone resolution at the Security Council will be a telling moment for such critics. Some council members, namely Russia and China, may nix the idea. Russian official said they would examine who would enforce the no-fly zone before deciding whether to sign it, Fox News reported. China, which like Russia has veto power, may oppose the resolution.

In the forefront of the push for a resolution is France. As rebels fighting Qaddafi's forces lose ground, retreating from their last stronghold west of Tripoli Tuesday, French Foreign Minister Alain Juppe said in a radio interview that had the international community acted last week, the rebels would be in a much stronger position.

But world leaders including President Obama are insisting that the response to Libya must be multilateral and come through international organizations. Mr. Obama's willingness for the US to take a back seat is making room for others, beginning with some in the region, to act.

Moreover, global political reaction to the uprisings in North Africa has emphasized universal values and human rights rather than countries' strategic interests – mirroring traditional UN policy. For the moment, at least, the world seems to be moving toward the UN's view of things, and that has given the international organization a rising "relevance."

"It's true that Qaddafi's particularly egregious actions have spurred the international community in ways that another crisis might not have, and that has forged a unity in the organization that we don't see every day," says Edward Luck, senior vice president at the International Peace Institute in New York. "But we're also seeing the invoking of universal norms and standards that go to the heart of what the UN is about, and that's something you wouldn't have imagined even a few months ago."

For example, regional organizations like the Arab League and the Organization of the Islamic Conference set the tone with strong statements on Libya that encouraged the UN to take more forceful action. The Security Council resolution on Libya, which passed unanimously, took those cues and invoked an emerging "responsibility to protect" doctrine. In effect, it advanced the idea that a leader who either fails to protect the country's population or openly attacks it is opening the door to international intervention.

That reference, combined with the council's referral of Qaddafi to the ICC, suggest that the UN is at the forefront of an effort to redefine national sovereignty, subjecting the governing class in any country to the threat of international intervention if they do not uphold rights and values central to the UN's character and mission.

This threat of international intervention "is a serious factor people have to take into consideration," says Lynn Pascoe, the UN's undersecretary-general for political affairs.

"If you have your war planes out there shooting people, it's going to cost you – and that's a good thing."

On one hand, it is somewhat surprising that the Security Council would be willing to make such a strong statement. Its makeup this year includes several revolving members such as India and Brazil who are hoping for a permanent seat some day. But rather than acting as a drag on action, they have been catalysts.

"The new aspirants are eager to show that the Security Council is a serious place," says a senior UN official. "They don't want to throw sticks in the spokes, they're out to show the Security Council can work."

Yet critics counter that for all these heady ideals, UN action on Libya has not amounted to anything tangible.

"The UN has basically been irrelevant on Libya," says John Bolton, the former US ambassador to the UN under President Bush. "There's no evidence the sanctions or the referral to the ICC has had the slightest impact on the ground. I can appreciate that the diplomats are feeling the need to do something," he adds, "but so far at the UN it's been the usual – all talk and no action."

Mr. Bolton says action against Qaddafi would be more definitive if based on the critical national interests at stake – and if the action were led by the US. "There are at least three key American interests in the balance here, and that should be more than enough to act," he says.

Bolton says these interests are:

1. Qaddafi has never paid for the Lockerbie airliner bombing and the Berlin disco bombing that killed American servicemen.

2. If the situation in Libya goes unresolved, it could leave the country in chaos, creating a "Somalia situation" that opens the door to Al Qaeda setting up shop.

3. Qaddafi, if victorious, "would very likely decide to resume his nuclear program."

Secretary of State Hillary Rodham Clinton met with Libyan opposition leader Mahmoud Jibril in Paris Monday to discuss ways in which the US could aid rebel efforts. Mr. Jibril asked for US military assistance and enforcement of a no-fly zone over Libya, US officials said. Secretary Clinton has said the US would not support a no-fly zone without UN backing.

Even US proponents of the UN, who argue that the UN is experiencing a renewed sense of purpose in the wake of the Middle East upheaval, say the jury is still out on its actions.

"This is a really tough test," says Mr. Luck of the International Peace Institute. "What the institution faces now are the risks of relevance." In short, it needs to deliver on rising expectations, he says.

Others caution that disappointment is bound to develop because the UN is invoking moral authority, which cannot deliver as immediate a response as military action might.

"The problem is that the kinds of actions the UN is taking are really long term in their delivery, but in many ways the international institutions will be judged by what happens in the short term," says Monica Serrano, director of the Global Center for the Responsibility to Protect in New York.

She notes, for example, that other leaders seeing the international pressures placed on Qaddafi might think twice before following in his footsteps, but such impact won't be immediately apparent.

Yet no matter how the Libya crisis plays out, what seems certain is that the global perception of what role the UN should play in such situations has evolved dramatically in a decade.

"A lot of people 10 years ago would have looked at Libya and said, 'That's a domestic issue,' " Luck says. "Now you have Libya's peers calling on the UN for action, which suggests a shift in values and in what catalyzes an international response that is really quite striking."